Interlaced magnetic recording (IMR) is a storage technique that utilizes different track widths, sometimes with different linear densities, when writing alternating data tracks on a storage medium. For example, every-other track is written to have a wide track width, and the alternating, interlaced tracks are written with a comparably narrower width. In IMR systems, the tracks are spaced such that each one of the narrow (top) tracks overlaps and overwrites a small portion of the edges of the immediately adjacent wider (bottom) tracks. In some systems, write access rules prohibit data from being written to a narrow IMR track until data is first stored on the two contiguous (physically adjacent) wider IMR tracks. For this reason, the narrow data tracks in IMR are often referred to as “top tracks” while the wider data tracks are referred to as “bottom tracks.”
In some implementations, IMR devices utilize a higher bit density when writing the wider (bottom) data tracks than the narrower (top) data tracks. As a result of this variable bit density, the variable track width, and the overlap between edges of adjacent tracks, a higher total areal density can be realized in IMR systems than that attainable in systems that implement the same magnetic recording type without utilizing alternating tracks of variable width and linear density.